Ricochet of Spheres on Sand of Various Temperature

  • Yoon Keon Kim Department of Mechanical Engineering, Korea University, Korea
  • Woo Chun Choi Department of Mechanical Engineering, Korea University, Korea
Keywords: Ricochet, Debris, Shear stress, Internal frictional angle, Safety distance


The debris generated by the explosion of a building or ammunition is flown far away through the ricochet phenomenon. The debris contains a very large amount of energy, and a risk factor surrounding it may be applied. The safety distance from debris is set from experiments or FEM analysis. The ricochet of debris is affected not only by the initial conditions of the debris, but also by the conditions of the medium. In this paper, the effect of sand temperature on the ricochet of sphere projectiles was investigated through experiments and FEM, by measuring the shear stress and internal friction angle when the sand temperature increases. As the temperature of the sand increases, the shear stress and the internal friction angle decrease, and the penetration depth of the projectile increases. As the depth of penetration becomes longer, the kinetic energy is lost more by the friction force with the sand and, the sphere projectile speed decreases more. This is mainly caused by the energy loss of the projectile, so the kinetic energy of the ricocheted projectile is reduced. Therefore, when setting the optimized inhabited building distance (IBD), the conditions of the medium should be taken into account.

Author Biographies

Yoon Keon Kim, Department of Mechanical Engineering, Korea University, Korea
Mr Yoon Keon Kim, received his BS (Mechanical Engineering) from Myongji University, Republic of Korea. He is currently pursuing his PhD from Korea University at Precision Technology Laboratory, Seoul, Republic of Korea. His areas of interests are ricochet phenomenon of debris and projectile onto various medium, projectile penetration in sand, and FEM analysis for ricochet and penetration.
Woo Chun Choi, Department of Mechanical Engineering, Korea University, Korea
Dr Woo Chun Choi, received his BS and MS in Mechanical Engineering from Seoul National University, Republic of Korea, in 1982 and 1984, respectively. He obtained his PhD (Mechanical Engineering) from MIT in 1990. He is presently working as Professor at Department of Mechanical Engineering in Korea University, Republic of Korea. His research area includes precision engineering, and manufacturing processes.
How to Cite
Kim, Y. K., & Choi, W. C. (2018). Ricochet of Spheres on Sand of Various Temperature. Defence Science Journal, 68(2), 150-158. https://doi.org/10.14429/dsj.68.11846
Armaments & Explosives